This invention relates to fluid transfer structures, and more particularly, to such structures incorporated in a rotary shaft member in a power transmission for providing plural parallel flow paths for lubrication and clutch pressure feed.
Prior art devices have used tubes inserted within a central bore of a shaft to provide a lube or cooling circuit and a parallel pressure feed circuit which are sealed from each other. These devices supply fluid to radial passages spaced along the shaft but do not generally control the amount of fluid distribution to any individual radial passage. The fluid admitted to a particular radial lube passage has been controlled by an orifice formed in each of the radial passages. This, of course, requires accurate machining and generally the use of a stepped drilling operation or two distinct drilling operations. If the orifices are of different sizes, additional machining complexity is encountered.
Other prior art systems simply provide sufficient lube fluid flow to maintain lubrication. These systems must provide more fluid than necessary to ensure proper lubrication and can suffer from reduced lubrication when other system demands are high. The fluid pump requirements are therefore increased resulting in increased energy consumption and reduced efficiency.